Hi all, I could use some advice....I received my new Rotax from Van's a couple months ago. In preparation for the first engine start, I have been adding all the fluids, etc. I noticed a random drop of fresh oil on the floor, directly under the oil tank. It appears to be coming from these strange indentations on the bottom of the tank. I have no idea what these marks are for?? The oil is not coming from the drain plug or washer. I guess I could fill them in with pro-seal, or should I just drain the tank and get it replaced under warranty? Thanks for any thoughts...

Ahh, that would make sense. I guess you would safety wire the drain bolt to that? I am guessing it was cut a little too deep and punctured the threaded hole for the drain plug. Looks like I need a new oil tank?

Paul -- Those indentations are for the safety wiring of your drain plug to the oil tank. These indentations typically have small holes drilled horizontally through them for the passing of the safety wire. They certainly should not leak -- if they do, it may mean that the hole was inadvertently drilled into the fluid-holding portion of the tank. I would make sure it is in fact leaking before you drain the oil tank and inspect/test that area for a leak. If it is leaking there, that would seem to me to be a ROTAX warranty item. -- David

ps -- Always "double-wrench" that boss/plug when removing/tightening the assembly -- you might mess up the boss/tank bottom if over-torqued.

Thanks David, I did hold that boss with a wrench and torqued the drain plug just in case it was loose. I think the tank was compromised when they made the hole in the boss. At least now I know what I'm looking at, thanks for replies.

They are available from most of the Rotax parts suppliers - CPS, Lockwood, etc. I've used one for years on our 912 equipped Diamond and it helps ensure that the oil system is properly purged and primed after an oil change. You could use this to pressurize the oil tank before you drain it and check for a leak at the drain plug boss. In my opinion, you will want this kit anyway for future oil changes - go ahead and get it now for troubleshooting your current leak.

Surprised that it's coming from the safety wire hole. Myself and a couple of friends had this same issue, a slow leak from the drain plug. The threads on the drain plug are too loose at least on ours. All of us replaced the plug with the quick drain plug for Rotax sold by Aircraft Spruce. This plug was has much tighter threads and the leaks stopped. Just sharing this in case it's actually coming from the plug.

Thanks to all for the great advice. I was not aware of the oil system priming kit, I am going to buy one. The initial air purge of the oil system was not confidence inspiring, so I was not happy that I have to open up the system to test/replace the tank.

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